Method of load shedding to reduce the total power consumption of a load control system

Abstract

A method of automatically reducing power consumption in a load control system having a central controller and a plurality of load control devices controlling the amount of power delivered to a plurality of electrical loads, the method comprising the steps of configuring a load shedding tier defining a load shed parameter for each of the electrical loads; the controller determining the total amount of power presently being consumed by all of the plurality of electrical loads; the controller comparing the total amount of power to a threshold amount of power; the controller automatically transmitting a digital message to the plurality of load control devices if the total amount of power exceeds a threshold amount of power; and the load control devices controlling the amount of power delivered to the electrical loads in accordance with the load shed parameters of the load shedding tier in response to the digital message transmitted by the controller.

1 . A method of automatically reducing power consumption in a load control system having a central controller and a plurality of load control devices controlling the amount of power delivered to a plurality of electrical loads, the method comprising the steps of:
 configuring a load shedding tier defining a load shed parameter for each of the electrical loads;   the controller determining the total amount of power presently being consumed by all of the plurality of electrical loads;   the controller comparing the total amount of power to a threshold amount of power;   the controller automatically transmitting a digital message to the plurality of load control devices if the total amount of power exceeds a threshold amount of power; and   the load control devices controlling the amount of power delivered to the electrical loads in accordance with the load shed parameters of the load shedding tier in response to the digital message transmitted by the controller.   
   
   
       2 . The method of  claim 1 , further comprising the steps of:
 configuring a first load shedding tier defining a first load shed parameter for each of the electrical loads; and   configuring a second load shedding tier defining a second load shed parameter for each of the electrical loads.   
   
   
       3 . The method of  claim 2 , wherein the amount of power delivered to the electrical loads in accordance with the second load shed parameters of the second load shedding tier is less than the amount of power delivered to the electrical loads in accordance with the second load shed parameters of the second load shedding tier. 
   
   
       4 . The method of  claim 3 , wherein the step of the controller automatically transmitting a digital message to the plurality of load control devices if the total amount of power exceeds a threshold amount of power further comprises:
 the controller transmitting the first load shed parameters of the first load shedding tier to the load control devices if the total amount of power exceeds the threshold amount of power a first time; and   the controller subsequently transmitting the second load shed parameters of the first load shedding tier to the load control devices if the total amount of power exceeds the threshold amount of power a second time.   
   
   
       5 . The method of  claim 4 , further comprising the step of:
 storing the first and second load shed parameters of the respective first and second load shedding tiers in a memory of the controller.   
   
   
       6 . The method of  claim 3 , wherein the step of the controller automatically transmitting a digital message to the plurality of load control devices if the total amount of power exceeds a threshold amount of power further comprises:
 the controller transmitting a first load shedding command to the load control devices if the total amount of power exceeds the threshold amount of power a first time; and   the controller subsequently transmitting a second load shedding command to the load control devices if the total amount of power exceeds the threshold amount of power a second time.   
   
   
       7 . The method of  claim 4 , further comprising the step of:
 storing the first and second load shed parameters of the respective first and second load shedding tiers in a memory of the load control devices;   the load control devices controlling the amount of power delivered to the electrical loads in accordance with the first load shed parameters of the first load shedding tier in response to the first load shedding command; and   the load control devices controlling the amount of power delivered to the electrical loads in accordance with the second load shed parameters of the second load shedding tier in response to the second load shedding command.   
   
   
       8 . The method of  claim 2 , further comprising the steps of:
 determining if another load shedding tier exists in response to the total amount of power exceeding the threshold amount of power; and   providing an alert to a user if another load shedding tier does not exist.   
   
   
       9 . The method of  claim 8 , wherein the step of providing an alert comprises sending an email. 
   
   
       10 . The method of  claim 8 , wherein the step of providing an alert comprises printing an alert page with a printer. 
   
   
       11 . The method of  claim 8 , wherein the step of providing an alert comprises displaying a warning message on a display screen of a personal computer. 
   
   
       12 . The method of  claim 1 , further comprising the step of:
 configuring a plurality of load shedding tiers each defining a different load shed parameter for each of the electrical loads.   
   
   
       13 . A load control system for automatically controlling the amount of power delivered from an AC power source to a plurality of electrical loads, the load control system comprising:
 a plurality of load control devices coupled to each of the electrical loads for controlling the amount of power delivered to the electrical loads; and   a central controller operable to determine the total amount of power presently being consumed by all of the plurality of electrical loads, compare the total amount of power to a threshold amount of power, and automatically transmit a digital message to the plurality of load control devices if the total amount of power exceeds a threshold amount of power;   wherein the load control devices are each operable to control the amount of power delivered to the connected electrical load in accordance with a load shed parameter of a load shedding tier in response to the digital message transmitted by the controller.   
   
   
       14 . The load control system of  claim 13 , wherein the controller is operable to configure a first load shedding tier defining a first load shed parameter for each of the electrical loads and a second load shedding tier defining a second load shed parameter for each of the electrical loads. 
   
   
       15 . The load control system of  claim 14 , wherein the controller comprises a memory for storing the first and second load shed parameters of the respective first and second load shedding tiers. 
   
   
       16 . The load control system of  claim 15 , wherein the amount of power delivered to the electrical loads in accordance with the second load shed parameters of the second load shedding tier is less than the amount of power delivered to the electrical loads in accordance with the second load shed parameters of the second load shedding tier. 
   
   
       17 . The load control system of  claim 16 , wherein the controller is operable to transmit the first load shed parameters of the first load shedding tier to the load control devices if the total amount of power exceeds the threshold amount of power a first time, and to subsequently transmit the second load shed parameters of the first load shedding tier to the load control devices if the total amount of power exceeds the threshold amount of power a second time. 
   
   
       18 . The load control system of  claim 14 , wherein the controller is operable to determine whether another load shedding tier exists if the total amount of power exceeding the threshold amount of power, and to provide an alert to a user if another load shedding tier does not exist. 
   
   
       19 . The load control system of  claim 18 , wherein the controller comprises a display screen for displaying a warning message. 
   
   
       20 . The load control system of  claim 13 , wherein the controller comprises a memory for storing first and second load shed parameters of respective first and second load shedding tiers. 
   
   
       21 . The load control system of  claim 20 , wherein the controller is operable to transmit a first load shedding command to the load control devices if the total amount of power exceeds the threshold amount of power a first time, and to subsequently transmit a second load shedding command to the load control devices if the total amount of power exceeds the threshold amount of power a second time; and
 wherein the load control devices are each operable to control the amount of power delivered to the electrical loads in accordance with the first load shed parameters of the first load shedding tier in response to the first load shedding command, and in accordance with the second load shed parameters of the second load shedding tier in response to the second load shedding command.   
   
   
       22 . A central controller for a load control system having a plurality of load control devices for controlling the amount of power delivered from an AC power source to a plurality of electrical loads, the controller comprising:
 means for configuring a load shedding tier defining a load shed parameter for each of the electrical loads;   means for determining the total amount of power presently being consumed by all of the plurality of electrical loads;   means for comparing the total amount of power to a threshold amount of power; and   means for automatically transmitting a digital message to the plurality of load control devices if the total amount of power exceeds a threshold amount of power, such that the load control devices control the amount of power delivered to the electrical loads in accordance with the load shed parameters of the load shedding tier in response to the digital message.   
   
   
       23 . A load control device of a load control system for controlling the amount of power delivered from an AC power source to an electrical load, the load control device comprising:
 a load control circuit adapted to be coupled to the AC power source and the electrical load to control the amount of power delivered to the electrical load;   a control circuit coupled to the load control circuit for controlling the amount of power delivered to the electrical load;   a memory coupled to the control circuit and operable to store a first load shed parameter for a first load shedding tier; and   a communication circuit coupled to the control circuit and operable to receive a digital message representative of the total power of the load control system exceeding a threshold amount of power;   wherein the control circuit is operable to control the amount of power delivered to the electrical load in accordance with the first load shed parameter of the first load shedding tier in response to receiving the digital message a first time.   
   
   
       24 . The load control device of  claim 23 , wherein the memory is operable to store a second load shed parameter for a second load shedding tier, and the control circuit is operable to control the amount of power delivered to the electrical load in accordance with the second load shed parameter of the second load shedding tier in response to receiving the digital message a second time.